Pollutant emissions from “partially” mixed turbulent flames

Semerjian, Hratch G.; Ball, Irven C.; Vranos, A.

doi:10.1016/s0082-0784(79)80067-3

Cited by 9 publications

(7 citation statements)

References 2 publications

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“…The results of Semerjian et al (15) are shown for comparison in Fig.4 and these show unburnt hydrocarbon levels very much lower than the present and similar to the direct propane injection results. Lower levels would be expected due to the higher inlet temperature, but other factors may be involved.…”

Section: Unburnt Hydrocarbon Emissionssupporting

confidence: 86%

“…The only work similar to the present is that of Semerjian et al (15) who studied emissions form a grid plate stabiliser with a central pressure jet atomiser with a 45 0 cone angle and Jet -A fuel. Their test installation was very similar to the present, but their inlet temperature was 756 K. At this inlet temperature flame stability was better than for the present arrangement.…”

Section: Fig4 Unburnt Hydrocarbon Emissionsmentioning

confidence: 96%

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Mixing and Fuel Atomisation Effects on Premixed Combustion Performance

Andrews

Aziz

Al-Dabbagh

1983

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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The main objective was to compare a flame stabiliser at constant pressure loss and identical isothermal aerodynamics with three modes of fuel injection: premixed, direct propane injection and direct kerosene injection. A Jet Mixing type of flame stabiliser was used at simulated gas turbine primary conditions. The influence of gaseous mixing effects was to deteriorate the combustion efficiency solely by increasing the CO emissions and to increase the NOx emissions. The flame stability was increased and low CO emissions were achieved at weaker mixtures. Liquid fuel atomisation effects resulted in a further deterioration in combustion efficiency due solely to un-burnt hydrocarbons. However, the NOx emissions were reduced indicating that local stoichiometric burning around single droplets does not occur.

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Section: Unburnt Hydrocarbon Emissionssupporting

confidence: 86%

Section: Fig4 Unburnt Hydrocarbon Emissionsmentioning

confidence: 96%

Mixing and Fuel Atomisation Effects on Premixed Combustion Performance

Andrews

Aziz

Al-Dabbagh

1983

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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“…For low equivalence ratios, they found that NO emissions decreased by a factor of ten as a result of better fuel-air mixing. In a similar study by Semerjian et al (1979) it was found that poorer fuel-air mixing resulted in increased NO emissions for overall fuel-lean flames. Lyons (1981) used a multipoint fuel injector spraying Jet A fuel to achieve different equivalence ratio profiles across the diameter of the flametube.…”

Section: Droplet and Spray Evaporationmentioning

confidence: 87%

The Role of Fuel Preparation in Low Emissions Combustion

Lefebvre

1995

Volume 5: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation;

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The attainment of very low pollutant emissions, in particular oxides of nitrogen (NOx), from gas turbines is not only of considerable environmental concern but has also become an area of increasing competitiveness between the different engine manufacturers. For stationary engines, the attainment of ultra-low NOx has become the foremost marketing issue. This paper is devoted primarily to current and emerging technologies in the development of ultra-low emissions combustors for application to aircraft and stationary engines. Short descriptions of the basic design features of conventional gas turbine combustors and the methods of fuel injection now in widespread use are followed by a review of fuel spray characteristics and recent developments in the measurement and modeling of these characteristics. The main gas turbine generated pollutants and their mechanisms of formation are described, along with related environmental risks and various issues concerning emissions regulations and recently-enacted legislation for limiting the pollutant levels emitted by both aircraft and stationary engines. The impact of these emissions regulations on combustor and engine design are discussed first in relation to conventional combustors and then in the context of variable-geometry and staged combustors. Both these concepts are founded on emissions reduction by control of flame temperature. Basic approaches to the design of “dry” low NOx and ultra-low NOx combustors are reviewed. At the present time lean, premix, prevaporize, combustion appears to be the only technology available for achieving ultra-low NOx emissions from practical combustors. This concept is discussed in some detail, along with its inherent problems of autoignition, flashback, and acoustic resonance. Attention is also given to alternative methods of achieving ultra-low NOx emissions, notably the rich-bum, quick-quench, lean-burn and catalytic combustors. These concepts are now being actively developed, despite the formidable problems they present in terms of mixing and durability. The final section reviews the various correlations which are now being used to predict the exhaust gas concentrations of the main gaseous pollutant emissions from gas turbine engines. Comprehensive numerical methods have not yet completely displaced these semi-empirical correlations but are nevertheless providing useful insight into the interactions of swirling and recirculating flows with fuel sprays, as well as guidance to the combustion engineer during the design and development stages. Throughout the paper emphasis is placed on the important and sometimes pivotal role played by the fuel preparation process in the reduction of pollutant emissions from gas turbines.

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“…Mitrovic and Lee (1998) used a laser induced incandescence (LII) setup to measure the soot volume fraction in ethylene partially premixed flames. Semerjian et al (1979) studied emissions of NO x , CO and Total Hydrocarbons (THC) with respect to the local equivalence ratio for a 'partially' mixed flame. The idea behind keeping the fuel constant was to fix the carbon content, so that any changes in the soot concentration can only be attributed to changes in the efficiency of combustion or the chemistry, rather than due to any change in the fuel content.…”

Section: S Kohli and A Kusharimentioning

confidence: 99%